A document where you know what information you are looking for, as well as where on the document that information is located. That is, the layout is known. Examples: Questionnaires, surveys, mail order forms, tax return forms, checks, payment orders, consignment notes.
Structured documents, and their fields or classifiers, are specified by adding a layout, or image of the document, to the document specification. Document layouts are listed under the main document specification when you open the document specification editor.